New Motor New Problems

I recently build a 351w stroked to a 408 with almuminum heads a fat cam, I just started it for the first time a week ago. I ran it for less the 20 minutes, never in one sitting, just starting it for a second to adjust something then shut it off. I was putting in antifreeze and getting it to circulate by letting the engine warm up when it started popping out the carb. I moved the timing around (no timing light available at the time) but it didnt help. I left it alone because i was not sure what was going on. Anyone got any ideas?

Thanks

If that "fat cam" is a flat-tappet, either hydraulic or solid, you have flattened an exhaust lobe.

If it's a roller, you probably bent an intake valve.

The proper break-in procedure for a flat-tappet cam is among the MOST important aspects of a new engine.
You need to fire it up, rev to about 2,500 and hold it there for the first 15-20 minutes. NEVER allow it to idle during this period. We always have two people involved. One to watch tach, temp and oil pressure, and the other watches the engine for leaks, etc.

If this is the case, please, do NOT post this as a cam failure. The vast majority of "cam failure" posts we see on this forum and others, are installer related, rather than parts failure.

Jim